The challenge of integrating small and efficient electrically pumped light sources in silicon based photonic circuitry is well known.
Gunn (Photonics Spectra March 2006, pp. 62-67) described this challenge and proposes a solution where light is provided from non-integrated external laser sources. Through an optical fibre, the light is directed to an integrated holographic lens and thereby coupled to an integrated waveguide. This approach has the disadvantages that tedious alignment and subsequent packaging is necessary.
Fang et al. (Optics Express 14, pp. 9203 (2006)) describes an edge-emitting electrically pumped AlGaInAs-silicon evanescent laser architecture. The architecture is wafer bonded to a silicon on insulator (SOI) substrate and the laser cavity is defined solely by a silicon waveguide in the underlying SOI substrate. While solutions based on edge-emitting lasers provides easier coupling to photonic circuitry, they have the disadvantages of relatively high power consumption and non-intrinsic single mode control.
Hence, an improved way of integrating light sources on silicon platforms would be advantageous, and in particular a more efficient and/or reliable ways of providing light to photonic circuits would be advantageous.